Calcinable ring in thermoplastic material for taking imprints when making permanently fixed false teeth

ABSTRACT

This invention relates to the taking of imprints for permanently fixed false teeth. The ring forming the subject matter of the invention is made of calcinable thermoplastic material and is of substantially cylindrical shape with a wall thickness of 0.3 0.4 mm and a height of 8 - 12 mm, the ring being provided to suit diameters increasing by 0.5 mm for example over the range 4 to 13 mm approximately. Its cervical edge is indented. To obtain the imprint, this ring is fitted on to the stump of the tooth to be replaced and the imprint or model is then taken directly. This ring avoids the need for preparing a ring in special metal.

United States Patent [151 3,686,754 Kondoloff Aug. 29, 1972 [54] CALCINABLE RING IN 3,530,585 9/1970 THERMOPLASTIC MATERIAL FOR TAKING IMPRINTS WHEN MAKING PERMANENTLY FIXED FALSE TEETH [72] Inventor: Joseph Charles Richard Kondoloff, 1 Place du March, 57 Saint Avold, France [22] Filed: Nov. 3, 1970 [21] Appl. No.: 86,541

[30] Foreign Application Priority Data Dec. 19, 1969 France ..6944029 [52] US. Cl ..32/17 [51] Int. Cl ..A6lc 9/00 [58] Field of Search ..32/17, 2

[56] References Cited UNITED STATES PATENTS 3,390,458 7/1968 Lytton ..32/17 Goldstine ..32/17 Primary ExaminerRobert Peshock Attorney-Young & Thompson [5 7 ABSTRACT This invention relates to the taking of imprints for permanently fixed false teeth. The ring forming the subject matter of the invention is made of calcinable thermoplastic material and is of substantially cylindrical shape with a wall thickness of 0.3 0.4 mm and a height of 8 12 mm, the ring being provided to suit diameters increasing by 0.5 mm for example over the range 4 to 13 mm approximately. Its cervical edge is indented. To obtain the imprint, this ring is fitted on to the stump of the tooth to be replaced and the imprint or model is then taken directly. This ring avoids the need for preparing a ring in special metal.

3 Claims, 5 Drawing Figures CALCINABLE RING IN THERMOPLASTIC MATERIAL FOR TAKING IIVIPRINTS WHEN MAKING PERMANENTLY FIXED FALSE TEETH BACKGROUND OF THE INVENTION The present invention relates in a general way to the making of permanently fixed false teeth and concerns more particularly the operations of taking the imprints necessary for this purpose.

When making and fitting a crown or bridge for example, it is usual to cut down the tooth or teeth concerned to a stump, then to measure the diameter of the stump with the help of an annular element or wire, to'make a ring, of copper for example, and to take the imprint on this ring. This method operation involves drawbacks well known to practitioners, particularly that of having to make a metal ring separately as a preliminary operation, and the object of the invention is to eliminate these drawbacks.

In one of its aspects, the invention resides in the provision of a ring made of calcinable thermoplastic resin and of substantially cylindrical form, this ring being in a form to suit a graduated range of diameters covering the span of the usual diameters of toothstumps and being adapted to be fitted on a stump so that the print can be taken directly.

In accordance with one advantageous feature, the ring forming the subject-matter of the invention is provided at least on its cervical edge with an opening permitting a good fit below the gum.

The material of which the ring is made can be any thermoplastic substance that is sufficiently deformable and can be modelled, that is to say, shaped to fit the form of the stump tightly, after having been slightly heated, for example by immersion in water at 4050 C., this deformability also facilitating fitting below the gum. To obtain the required deformability, the .ring preferably has a quite small wall-thickness, less than 0.6 mm for example and preferably as little as 0.3 to 0.4 mm. In order to suit tooth-stumps of different shapes, there can be provided sets of rings having a height which may vary from 8 to 12 mm for example, the diameter of the rings varying by 0.5 to 1 mm for example from one ring to another, and covering the diameter range of4 to 13 mm.

The invention also concerns a method for taking the imprints with a view to making permanently fixed false teeth, this method consisting in utilizing a ring as described above and selected to suit the perimeter of the stump, after softening of the ring if necessary, in then making a top imprint with a normal material for example, in then, if required, introducing a'sufi'lciently fluid correcting material into the imprint obtained with a view to this being compressed below the gum by the ring that remains in the imprint, in casting the imprint in a suitable material, the ring then serving the purpose of forming the cervical edge of the cast element, and in filling a prepared ring with a resin as far as the top imprint so as to obtain the precise configuration of the tooth stump, the form of the bite surface being obtained by chewing movements.

If necessary, a top imprint of the model is made to complete the elements of a bridge.

The use of rings made of calcinable thermoplastic resin as described above thus enables an imprint below the gum to be made without any prior preparation and enables an ideal cervical fit to be made of the crown portion and of the crown that has been made.

The following description which refers to the attached drawing and which is given by way of a nonlimiting example, will enable the invention to be better understood.

FIG. I is a perspective view of a ring that may be used in accordance with the invention.

FIGS. 2 to 5 show different stages in the taking of an imprint. I

The ring 1 which is illustrated in FIG. 1 and can be used for the taking of imprints for making false teeth, is

of basically cylindrical shape with an indented cervical edge. This ring is made of calcinable thermoplastic material which can be readily deformed at a temperature of 45 C. for example so that it can be moulded on to the stump of a tooth. The ring has a wall-thickness of from 0.3 to 0.4 mm and has a height of'8 to 12 mm and is one of a set of rings having different diameters. The method using this ring for making an imprint will be described by reference to FIGS. 2 to 5.

As can be seen in FIG. 2, the ring is first fitted on to the stump 2 of the cut-down tooth. To mould the ring on to the stump, it is first immersed in water at 45 C. approximately and this renders the ring readily deformable. The indented cervical edge la of the ring 1 provides a good fit below the gum. In FIG. 2, the numeral 3 indicates the root of the tooth and 4 the gum.

Once the ring has set hard again, a top imprint is made as shown in FIG. 3 with the help of a standard material such as an alginate, a thiocol, a silicone etc., indicated by the numeral 5 in FIG. 3, the numeral 6 designating the imprint mould. After hardening, the imprint is removed from the mouth of the patient.

After this operation, and as shown in FIG. 4, a correcting material 7 such as a fluid silicone or a fluid alginate is introduced into the imprint, the compression below the gum of this material being achieved by the blocking action of the ring 1 which is now incorporated in the imprint.

A suitable substance can now be poured into the imprint in known manner, the cervical edge of the required cast element being defined by the ring 1. As shown in FIG. 5, it is also possible to fill the ring 1, prepared in the manner described by reference to FIGS. 2 and 3, with a self-polymerizing calcinable resin to obtain the precise shape of the tooth-stump, thereby to produce a morpho-functional generated crown. The Y numeral 8 designates this resin and the numeral 9 a tooth on the opposite jaw, chewing movements enabling the configuration of the bite surface to be obtained.

Finally, a model is obtained, the, imprint of which enables the elements of a bridge to be formed.

Modifications constituting equivalent technical steps can be made to the methods above-described without thereby departing from the scope of the invention.

What is claimed is 1. A method for taking imprints for making false teeth, comprising the steps of selecting a ring from a set of rings made of calcinable thermoplastic material, whereby said rings have different diameters ranging from 4 to 13 mm approximately, the difference between one diameter and the next being 0.5 to 1 mm, said thermoplastic material being such as to be readily deformable at a temperature of 40 to 50 C., said ring being selected from said set of rings to suit the perimeter of a preliminary prepared stump, softening said ring at a temperature of 40 to 50 C. approximately, molding said ring on to said stump, taking a top imprint with a standard material, casting the imprint in an appropriate material, said ring serving to form the cervical edge of the cast element, and filling the prepared ring as far as the top imprint with a resin to obtain the precise configuration of the tooth stump, the bite surface being formed by chewing movements.

2. A method according to claim 1, comprising the step of introducing a relatively fluid correcting material into the imprint as taken, so that said material is compressed below the gum by the ring which remains in the imprint.

3, A method for directly producing a morphofunctional generated crown, comprising the steps of selecting a ring from a set of rings made of calcinable thermoplastic material, said rings having different diameters ranging from 4 to 13 mm. approximately, the difference between one diameter and the next being 0.5 to 1 mm, said thermoplastic material being such as to be readily deformable at a temperature of 40 to C., said ring being selected from said set of rings to suit the perimeter of a preliminary prepared stump, softening said ring at a temperature of 40 to 50 C. approximately, molding said ring onto said stump, filling the ring with a self-polymerizing calcinable resin, producing chewing movements in order to reproduce the configu ration of the bite surface to be obtained, and casting the desired morpho-functional generated crown. 

1. A method for taking imprints for making false teeth, comprising the steps of selecting a ring from a set of rings made of calcinable thermoplastic material, whereby said rings have different diameters ranging from 4 to 13 mm approximately, the difference between one diameter and the next being 0.5 to 1 mm, said thermoplastic material being such as to be readily deformable at a temperature of 40* to 50* C., said ring being selected from said set of rings to suit the perimeter of a preliminary prepared stump, softening said ring at a temperature of 40* to 50* C. mapproximately, molding said ring on to said stump, taking a top imprint with a standard material, casting the imprint in an appropriate material, said ring serving to form the cervical edge of the cast element, and filling the prepared ring as far as the top imprint with a resin to obtain the precise configuration of the tooth stump, the bite surface being formed by chewing movements.
 2. A method according to claim 1, comprising the step of introducing a relatively fluid correcting material into the imprint as taken, so that said material is compressed below the gum by the ring which remains in the imprint.
 3. A method for directly producing a morphofunctional generated crown, comprising the steps of selecting a ring from a set of rings made of calcinable thermoplastic material, said rings having different diameters ranging from 4 to 13 mm. approximately, the difference between one diameter and the next being 0.5 to 1 mm., said thermoplastic material being such as to be readily deformable at a temperature of 40* to 50* C., said ring being selected from said set of rings to suit the perimeter of a preliminary prepared stump, softening said ring at a temperature of 40* to 50* C. approximately, molding said ring onto said stump, filling the ring with a self-polymerizing calcinable resin, producing chewing movements in order to reproduce the configuration of the bite surface to be obtained, and casting the desired morpho-functional generated crown. 